Like the topic says, I have a problem with my driver's side sequential taillight. When I use my left turn signal it flashes bulbs 1 and 2 from right to left like it's supposed to but bulb 3 doesn't light up. I've checked the bulb and it's not blown. I've replaced it with other bulbs and that hasn't helped. All 3 bulbs light up when using the brakes and the hazards. I just can't seem to figure this out. Any info would be appreciated.